The Meebo team has created a application called Meebo repeater which acts as a proxy and makes it possible again to use Meebo if it is blocked.

Download the Meebo repeater from the Meebo website, and run it. The Meebo repeater will automatically configure the service and tell you the internet address that you will have to use to connect to Meebo. You might have to configure your firewall to allow Meebo repeater access to the net.